An immunochemical approach to the characterization of the capsular polysaccharides of Cryptococcus neoformans is proposed. Heteroglycans from several chains of the four recognized serotypes and mutants partially blocked in capsule synthesis will be fractionated based on differential complexation with cetyltrimethylammonium bromide, ion exchange chromatography, lectin affinity, and immunoaffinity. The native polysaccharides, polysaccharide derivatives and oligosaccharides derived by special chemical treatments, e.g., lithium: ethylenediamine, anhydrous hydrofluoric acid and periodate oxidation, will be examined by various analytical methods, including gas liquid chromatography, high field nuclear magnetic resonance spectrometry, gas liquid chromatography-mass spectrometry, and glycosidase susceptibility. The data obtained will be used to make linkage and sequence assignments for the native polysaccharides. Purified and immunochemically defined capsular polysaccharides and their derivatives will be used in the development of an enzyme immunoassay (EIA). This assay in conjunction with monoclonal antibodies will be used to delineate the chemical nature of the type specific and other immunodominant epitopes of C. neoformans. Structurally defined cryptoccal polysaccharides, their derivatives and model compounds will be studied by both direct and hapten inhibition variations of EIA.